Grafene indotto da laser per applicazioni di sensoristica e stoccaggio energetico

In recent years, novel methods for graphene synthesis, such as laser-induced graphene (LIG), have attracted substantial attention. Since its discovery in 2014, research on LIG has expanded into various fields, from sensing devices to energy storage applications. LIG presents a straightforward and economical synthetic approach, promising to fill the gap between laboratory-scale studies and industrial production. Its synthesis involves the laser irradiation of a polymeric substrate, typically polyimide, under specific laser settings. The resulting material is a conductive, porous carbon structure composed of few-layer graphene sheets. In this research project, LIG is explored as an electrode material for electrochemical glucose sensing and as an anode for both lithium-ion batteries (LIBs) and sodium-ion batteries (NIBs). The focus lies on developing a single-step method to decorate LIG with metallic nanostructures, simplifying synthesis while exploring light-matter interactions. The LIG composite materials were prepared by combining polyamic acid (PAA), the precursor of polyimide, with metal salt precursors and subsequently irradiating the mixture with a diode laser. This approach primarily induces a carbothermal reduction process, producing metallic nanoparticles (NPs) embedded in the LIG matrix. For electrochemical glucose sensing, LIG-Cu composites were developed, leveraging the catalytic activity of copper nanoparticles (Cu-NPs) towards glucose oxidation. The resulting LIG-Cu material consists of Cu-NPs encapsulated within a few graphene layers, forming a metallic core with a thin oxidized shell. Among the tested composites with varying copper concentrations, the optimal sample exhibited high sensitivity and reproducibility in glucose oxidation, suggesting strong potential as a biosensing material. Similarly, LIG composites with tin (Sn), antimony (Sb), and tin-antimony alloys (SnSb) were synthesized for battery applications. The structural analysis confirmed that the LIG matrix efficiently hosts Sn and Sb metallic NPs, as well as alloyed SnSb particles, all encapsulated by graphene layers. These composites were fabricated by casting the PAA and metal salt mixture directly onto copper current collectors, followed by laser treatment. When tested in half-cell configurations, both LIBs and NIBs demonstrated enhanced cycling stability and improved electrochemical performance, underscoring the versatility of LIG-metal composites as effective anode materials. Furthermore, the synthesis process was adapted to create tin sulfide (SnS) chalcogenides by modifying the starting polymer to polyether sulfone (PES) and adding a tin precursor salt. Structural characterization of LIG-SnS confirmed the successful formation of the desired SnS phase, with minor secondary phases present. Electrochemical testing of the LIG-SnS electrode in NIBs revealed promising stability and potential for energy storage applications. This study provides insights into the synthesis of LIG-metal composites using simple, scalable methods, demonstrating the adaptability of LIG in forming versatile composites suitable for both sensing and energy storage applications.